a flip-flop or latch is a circuit that has two stable states and can be used to store state information.

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S-R latch / flip- flop question

First I want to ask, why are S and R inverted when comparing an S-R latch with NAND and NOR gate. It just seems odd to me that they're being inverted. Secondly, why is a multi-transition behaviour a ...
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16 views

JK flip-flop and sequence network

State diagram of the sequence network S looks like the following for a jk flip-flop: Is this the right truth table for it? ...
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1answer
35 views

Logisim: “Oscillation apparent”

I am trying to simulate an RS master slave flip-flop in Logisim, and I have encountered the "Oscillation apparent" error. What does this error mean and how is it resolved? I am required to use two nor ...
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55 views

Encoder and one Digital Logic Problem [closed]

in following Encoder, the priority of bigger number is bigger. if the initial state is 0, ...
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22 views

Help me understand Mealy machine with D flip flops vs JK flip flops

So, the task is to implement a synchronous sequential circuit which detects the input sequence "1101" using D flip flops and standard logic gates (represent with Mealy machine with finite number of ...
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3answers
410 views

What is race around condition in flip-flops?

I've gone through two of my text books and consulted my teacher but nothing seems to clarify my doubts. The two versions of race-around which I've been taught are - When the S and R inputs of an ...
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57 views

D flip flop with asynchronous level triggered reset

Ref : Is making a D flip flop with asynchronous level triggered reset possible? My code : ...
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76 views

Clock divider circuit with flip D flip flop

I am using D flip flops in my clock divider circuit. I have started with one FF and moving up with the number of divisions I want to have in my clock. This is how I want my D ffs to work. Now I ...
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1answer
66 views

What is the inverted output for on a D flip flop?

I was asked to find the answer for this, it is a pretty vague question: On a D Flip Flop, what is the Q' output? Look this up and write your answer in your pre-lab report. I am trying to understand ...
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104 views

A simple clarification on latches and flip-flops

Here are two representations of a gated SR latch (first one from my book and the second one from Wikipedia): The part I don't understand are the S and R inputs, why are they reversed in these two ...
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25 views

Modeling Rocker Switch with Block Xilinx System Generator

I am working on a project for the detection of QRS complex. I would make it with Xilinx system generator. I need to detect the thresholds at the output of the block and to detect from the TRIGGER ...
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2answers
46 views

Unsure if this asynchronous D-Flip-Flop Verilog code makes sense

This is my code for an async-reset-set D-flip-flop. I'm using quartus, and the module compiles, but there is no way to check if my logic is valid. I could use some outside opinions. The reset is ...
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1answer
125 views

problem with making 1 bit RAM memory using transistors?

I'm trying to make 1 bit RAM using four transistor ( 2 NOR Gates ). I built the 2 copies of the following circuit: I connected a LED to the output "F". Also, I connected Another LED to the output ...
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3answers
138 views

Reset of a JK flip flop pulse indicator

I've made a circuit with 74HC109 JK flip flops. The purpose is to catch a pulse from two signals and for about 20 seconds keep the stored value (of which pulse came first). My problem is I need to ...
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3answers
40 views

Powering on specific pieces of circuitry in sequence

I'm trying to power on specific pieces of circuitry in sequence, and have one piece active at a time. I thought a decade counter would be the way to go but most people seem to think a decade counter ...
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4answers
90 views

JK Flip Flop toggle action

How does toggle action in a JK flip flop change to alternate states? When both inputs are 1 ,the output of nor gates is forced to 0,then how come they toggle ?
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42 views

How to initiate Preset and Clear in a JK flip flop?

I want to use a JK flip flop in order to create a toggle output. It is clear that both J and K should be set to 1, as well as the Preset and Clear inputs. In some schematics, a Monostable 555 ...
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2answers
133 views

Generate flip-flops using only combinational logic

Just for fun, I wanted to design and simulate D-type flip-flops using only combinational logic in Verilog (or SystemVerilog). I am using using Verilator for the simulation. My initial attempt, which ...
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2answers
201 views

BJT Astable Multivibrator

I have the basic knowledge about multivibrators, but I did not understand the working principles of the circuit schematic provided down below. I have done the basic research about how it works, but ...
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1answer
167 views

NAND gate in proteus

I am trying to make a JK flip flop circuit in proteus but 2 of the nand gates does not seem to be working. There are no errors provided. Two of the 2-input nand gates does not seem to show output ...
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2answers
54 views

VHDL - Flip Flop inferring on a signal

I have to design a circuit to count up to a number and return to zero. It must have a carry signal (which I named a_o in my circuit) as flag to show that the ...
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1answer
322 views

JK flip flop random start outputs

I am working on a project for college and I have to implement a sort of alarm using only MUX's and JK flip flops and a bread board. The problem I encountered is that whenever I power the whole circuit ...
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5answers
153 views

Understanding D flip flop function - what this thing does

I am trying to understand what a D flip flop does int he context of building a truth table, so I can design a synchronous divide-by-five circuit. That is, count to five and reset. I know I need 3 ...
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2answers
57 views

Unable to toggle SN74HC109

I'm a complete amateur, I've probably gotten a million things wrong with this already. I'm using an SN74HC109 dual j-k" flip-flop chip. I'm trying to toggle the led (forgot to add a resistor in the ...
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1answer
85 views

JK Flipflop design for conveyor project

I have a small project/problem I am working on. While running a conveyor belt continuously with items on it, I need to stamp every other item. I am using a photocell to detect if an item is ...
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1answer
72 views

momentary to on/off switch for 12v

I got some oem switches and I want to mod them into light switches. Here is my situation: I would like to use the oem switch since it has illumination and button that matches the car.I have already ...
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1answer
133 views

Proteus BJT Astable Multivibrator Simulation Error

I am pretty new in Proteus and made a simple flip flop circuit as shown below. When I run the simulation, the circuit does not work as intended. Both of the LEDs light up at the same time. (LEDs ...
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117 views

How do I find the Truth Table for Mealy State Machine?

This is a followup to my previous question: I have this assignment in college: You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are ...
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1answer
87 views

Mealy Safety Device with 2 inputs

I have an assignment in college and I would like to ask some questions: You are to design a Mealy state diagram for a safety device. Assume that two debounced push-buttons, A and B, are available ...
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1answer
64 views

Sequence detector

I have a few questions to ask about electronics.I am studying computer science in my first year and I have a logic design course where the professor is kind of old let's say and he expects us to study ...
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3answers
157 views

Need help in understanding MUX-NOT flip-flop

I need help in doing practice problem: A MUX-NOT flip-flop (MN flip-flop) behaves as follows. If M=1 the flip-flop complements the current state. If M=0, the next state of the flip-flop is equal to ...
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1answer
50 views

Need help with pspice simulation

I made a project of monostable flip flop using 555 timer in pspice. Now I need help with simulation. Problem is that I'm just statring my adventure with pspice and I have no clue what I'm doing wrong. ...
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1answer
53 views

D flipflop in keypad

Why D flipflop is used in keypad for LCD ( U2 in schematic shown below ). Is it for buffer? unidirectional or bidirectional?
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57 views

24 Hour Counter JK Flip Flop

I'm trying to implement a 24 hour clock circuit using JK Flip Flops. I've gotten the minute part but I am having trouble designing the hours part, specifically the ones section. If it should count ...
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94 views

Mealy machine to detect sequence of 2 inputs

I have the following assignment for a project at college and I have a few questions regarding it. You are to design a Mealy state diagram for a digital lock. Assume that two debounced push-buttons, A ...
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2answers
91 views

Building circuit for n-relays using flip flops, is this the best solution?

I'm trying to build a circuit for n relays, each relay should hold it's state (ie latched). My first Idea was to use decoders, but clearly this was a bad option, since the state of the relays won't ...
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1answer
113 views

How would you make a 3-bit binary adder that adds two instead of 1?

I am trying to make an asynchronous adder that holds three bits and adds two to the number. Can someone help? A Google search shows nothing and I'm having a hard time visualizing how to make the ...
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40 views

Kmap Implementation in Electronics Workbench

I'm working in Electronics Workbench and after simplifying two of the Kmaps, I got values : Jd=1 & Kd=1 How would I implement that in the circuit? I know it looks confusing at the moment.
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1answer
123 views

LFSR Using D Flip Flops

I am fairly new to the VHDL language and I will admit that I primarily use it for educational purposes. I have been attempting to design a data encryption circuit using D flip flops. Obviously, an ...
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1answer
45 views

Help designing a serial adder [closed]

I need to build a circuit that adds two n-bit 2's complement numbers. the two numbers have to be stored in shift registers. The circuit should start with the least significant bits of each number and ...
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1answer
69 views

FSM for predesignated process (How to draw the state diagram)

let me start by saying this involves some homework problems so if you could help guide me a bit I would greatly appreciate it. I have been working with finite state machines for a bit in my course ...
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59 views

Parallel-in, parallel-out, universal shift register

I am trying build circuit of parallel-in/parallel-out universal shift register. I have found circuit in the Internet. Here it is I have tried to do this using MicroCap , but it doesn't work as ...
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44 views

Continuous Wave with flip-flops

What I'm going for is imagine 6 LED outputs, every other one on. (Off first) What I need to have happen is after I toggle on the 1 input to 1, it sets off a chain reaction, like a wave, where every ...
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1answer
78 views

Truth Table for JK flip-flop circuit?

Given a JK flip-flop circuit (using a D flip flop with a 2 by 1 MUX) how can I derive a truth table from this circuit? D = JQ' + K'Q Note: This is NOT a homework question. I just simply want to ...
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1answer
81 views

Does the output of JK Flip Flop toggle continously?

As given in most of the texts and online resources, the JK flip-flop requires a clock signal with an edge detector circuit so that the flip flop will be sensitive to the inputs only when the clock ...
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84 views

flip flop transfer function

Can same one explain me, if possible, how to get the equation of the transfer function for flip flop like the one below and hence get a plot like this
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1answer
153 views

Can someone explain to me what the 1s catching problem is in the Master Slave Flip Flop?

I have read the explanation in my textbook but I feel that they are too complex and no matter how much I try to understand it I don't seem to get what the difference is when the 1s complement occurs. ...
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1answer
66 views

How to toggle a reset in a counter made up of JK flip flops

I have been playing around with a small circuit which at the moment consists only of a counter made up of 3 JK flip flops. Like so: What I want to add is a reset input pin that will set the 3 LEDs ...
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1answer
34 views

connected d flip flop, propagation time = hold time?

When we connect two d flip flops, the propagation time and hold time have to be the same? or the propagation time have to be bigger than the hold time? I'm really confused please help!!
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266 views

Toggle two different LEDs with one T Flip flop

Imagine we have one green LED, one blue LED, power supply and resistors and grounds. We also have a switch. Can we toggle between the two different LEDs when the switch is pushed? If the blue LED is ...